The continuing work in inverter circuits aimed at reasonably satisfying the efficiency and load requirements of the fluorescent lamp, but with increased emphasis of circuit simplicity and reduced cost has brought about this invention. The principal object of this work is to provide the most simple electronics for providing fluorescent light from a low voltage battery. My previous work has already described the outstanding advantages of the fluorescent lamp as the light source as opposed to the incandescent lamp. This advantage becomes more important when portable lighting sources (electric lanterns) are being considered. The lumens of light per watt of electric energy has a direct bearing on the cost, size, weight, etc. of the internal battery element.
The rechargeable battery technology has, on the other hand, experienced dramatic success in producing small, economical, rechargeable, and totally sealed batteries. These sealed batteries require a reasonable degree of protection during charging to preclude damage from overcharge. However, these sealed batteries do not limit themselves to the use of a charge indicator such as, for example, gravity balls that are used to determine state of charge in the liquid lead-acid battery. Therefore, a further intent of this invention is to teach the use of the same electronic circuitry required for the inverter with minimum additions of complexity can be used to prevent over-charge of the sealed storage battery, and also to give the user a visual indication of when the battery has reached a complete charged state.